This invention relates to a semiconductor device. More particularly, it relates to a silicon solid state temperature responsive switch.
There are many applications for a device that will conduct or block electrical current flow up to a predetermined temperature and will switch over to the opposite state above that temperature. Temperature sensitive devices of a variety of types have been used in the past for thermally responsive electrical switches. Among these devices are thermocouples, bi-metal thermal expansion switches, thermistors, and the like. Each of these devices have unique characteristics that make them quite suitable for selected applications. We have found a new solid state temperature responsive switch that is suitable for a variety of applications. For example, it can be directly incorporated in a monolithic circuit, as well as be made as a discrete electrical component. Our device can be made and the switching temperature set with the usual type of techniques employed in making semiconductor devices, including integrated circuits. As a result, numerous advantages are inherently possible including better circuit compatibility, lower cost, smaller size circuits, etc. Moreover, our solid state device can be made so that it is insensitive to polarity of a constant voltage source applied, and is useful with alternating current as well as direct current sources.